localization with rssi method at wireless sensor networks osman ceylan electronics engineering phd...
TRANSCRIPT
Localization with RSSI Method at Wireless Sensor
Networks
Osman Ceylan
Electronics Engineering
PhD Student, Istanbul Technical University, Turkiye
28.10.2009
ITU WSN TEAM
Presantation Plan
• Networks−Computer Networks−Wireless Sensor Networks
• Hardware specifications• Advantages
• Localization Problem−Localization techniques−RSSI Method
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Networks• Computer Networks
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Networks• Wireless Sensor Networks
RemoteControl
LocalControl
Event
Event
Nodes
Alternativepath
Sensor area
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Wireless Sensor Networks−Wireless sensor networks and computer
networks are similar.• Able to send/receive data• Internal control unit
−But there are some significant differences.• Very small hardware• Wireless communication
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Hardware Specifications• Hardwares are low power small devices.
− Working with battery for 6-24 months
− Easy installing and carring
• Communicaton is wireless.− Generally uses ISM bands ( Especially 433 MHz and 2.4
GHz)− Low communication range (up to 200 meters at
outdoor)
• Microcontroller is processing unit.− Analog and Digital I/O− Internal RAM, Flash
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Advantages of WSN’s Versus Wireless Computer
Networks• Wireless sensor networks can be designed and
implemented much more bigger than computer
networks easily and cheaply.
• Network organization can be setted up
automatically by the hardwares.
• Hardwares:−Very low power consumption−Very low failure rates
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Localization Problem
• How can we find an object’s exact
position?−Triangulation
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Localization Techniques•GPS
−Only outdoor−1-15 meters error
•GSM−Bad in cities−100 meters error
•Sensor Networs−Ultrasonic Based Systems
•Very High Accuricy (under 5 cm), but very low range (max 10 meters)•Hard setting up•Not user friendly
−RSSI Based Systems•1 meter error
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RSSI Method• Received Signal Strength Indication is a
measurement of the received signals power.
• Radio frequency signals’ power decreases with
the distance:− Loss (dB) = 20log(d)+20log(f)+32.45− d=km, f=MHz
• We know communication frequency and
transmit power.So if we can measure received
signals power’s: We can find the distance d.−Received Power = Transmited power – Path
Loss
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RSSI Method
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Fixed Nodex3,y3
Fixed Nodex2,y2
Fixed Nodex1,y1
Fixed Nodex4,y4
MovingNode
R1
R2
R3R4
Advantages of RSSI Method at Localization
• No directional sensor like ultrasonic systems
• Indoor and outdoor usage
• Data communication and sensor usage at same
hardware
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Difficulties at RSSI Method
• Distance calculation is related RF
signal power at receiver.−Multipath propagation−Fading effects−Bad frontend devices
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Industrial Usage
• Data collection−Sensor datas collecting
• Temperature maps producing
• Tracking and location−Object tracking at production lines−Person tracking at hospitals,
penitentiaries−Animal tracking at farms
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Defence Systems
• Ammunition Tracking in a war or
storage
• Soldier Tracking in a war or trainging
• Detecting ally or enemy
• Data collection−For a person dead/alive−For a object existing/operating/moving
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Team
• Electronics Circuits and Antennas
Design Team−1PHd, 4 BSc
• Embedded Design Team−2 Msc, 6 BSc
• Command-Control Software Design
Team−1 MSc, 4 BSc
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Thanks
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